The reason for the short circuit of the PCB circuit board and the method of checking the short circuit

 Circuit board short circuit is a problem that every circuit board manufacturer encounters almost every day, and this problem has always plagued production and quality management personnel. It caused replenishment and overdue delivery due to insufficient shipments. , Customer complaints are more difficult for people in the industry to solve. The following editor will talk about the reasons for the short circuit of the circuit board and the method of checking the short circuit in detail.

Types of circuit board short circuit:

1. Short circuit can be divided into: Welding short circuit (such as tin connection), PCB short circuit (such as residual copper, hole bias, etc.), device short circuit, assembly short circuit, ESD/EOS breakdown, micro short circuit in the circuit board, electrochemical short circuit (such as chemical residue, Electromigration), short circuit caused by other reasons.

2. The short circuit can be classified into:

Line to line short circuit, line to face (layer) short circuit, face to face (layer to layer) short circuit.

PCB circuit board short circuit inspection method

Use the PC to open the PCB design drawing, light up the short-circuit network, and observe which locations are the closest and the easiest to connect to. Especially need to pay attention to the short circuit inside the IC.

If it is manual welding, you need to develop a good habit:

1. Visually inspect the PCB before soldering, and use a multimeter to check whether the critical circuits (especially the power supply and the ground) are short-circuited;

2. Every time a chip is soldered, use a multimeter to check whether the power supply and ground are short-circuited;

3. Don't throw the soldering iron randomly during soldering. If you throw the solder onto the solder feet of the chip (especially surface mount components), it will not be easy to find.

A short circuit was found. Take a board to cut the line (especially suitable for single/double-layer boards), and then power on each part of the functional block separately and eliminate it step by step.

Using short-circuit locating and analyzing instruments, for some conditions under specific circumstances, the detection efficiency of using instruments and equipment is higher, and the detection accuracy rate is also higher.